J/ApJS/266/15 The Lyα Reference Sample (LARS). XIV. (Melinder+, 2023)
The Lyα Reference Sample.
XIV. Lyα imaging of 45 low-redshift star-forming galaxies and inferences
on global emission.
Melinder J., Ostlin G., Hayes M., Rasekh A., Mas-Hesse J.M., Cannon J.M.,
Kunth D., Laursen P., Runnholm A., Herenz E.C., Messa M., Schaerer D.,
Verhamme A., Rivera-Thorsen T.E., Guaita L., Marquart T., Puschnig J.,
Le Reste A., Sandberg A., Freeland E., Bridge J.
<Astrophys. J. Suppl. Ser., 266, 15 (2023)>
=2023ApJS..266...15M 2023ApJS..266...15M
ADC_Keywords: Galaxies, radius; Redshifts; Ultraviolet; Equivalent widths;
Photometry, HST; Extinction; Optical
Keywords: Emission line galaxies ; Galaxies ; Lyman-alpha galaxies ;
Starburst galaxies ; Astronomical methods ; Observational astronomy
Abstract:
We present Lyα imaging of 45 low-redshift star-forming galaxies
observed with the Hubble Space Telescope. The galaxies have been
selected to have moderate to high star formation rates (SFRs) using
far-ultraviolet (FUV) luminosity and Hα equivalent width
criteria, but no constraints on Lyα luminosity. We employ a
pixel stellar continuum fitting code to obtain accurate
continuum-subtracted Lyα, Hα, and Hβ maps. We find
that Lyα is less concentrated than FUV and optical line emission
in almost all galaxies with significant Lyα emission. We present
global measurements of Lyα and other quantities measured in
apertures designed to capture all of the Lyα emission. We then
show how the escape fraction of Lyα relates to a number of other
measured quantities (mass, metallicity, star formation, ionization
parameter, and extinction). We find that the escape fraction is
strongly anticorrelated with nebular and stellar extinction, weakly
anticorrelated with stellar mass, but no conclusive evidence for
correlations with other quantities. We show that Lyα escape
fractions are inconsistent with common dust extinction laws, and
discuss how a combination of radiative transfer effects and clumpy
dust models can help resolve the discrepancies. We present an SFR
calibration based on Lyα luminosity, where the equivalent width
of Lyα is used to correct for nonunity escape fraction, and show
that this relation provides a reasonably accurate SFR estimate. We
also show stacked growth curves of Lyα for the galaxies that can
be used to find aperture loss fractions at a given physical radius.
Description:
The observational strategy for the Lyα Reference Sample (LARS)
is described in detail by Ostlin+ (2014ApJ...797...11O 2014ApJ...797...11O), and the same
strategy for imaging Lyα emission from a combination of broad-
and narrowband HST filters is employed for the extended sample.
All observations were carried out using HST with three different
cameras: ACS/Solar Blind Channel (SBC), ACS/Wide Field Camera (WFC),
and Wide Field Camera 3 (WFC3)/UVIS. A list of which filters were used
for the individual targets can be found in Table 7. While we used
archival data when available, the bulk of the data set consists of
observations from HST program 12310 (Ostlin+ 2014ApJ...797...11O 2014ApJ...797...11O, the
original LARS, observed from 2010-2012), and HST program 13483 (ELARS,
observed from 2013-2014). The observations for Tol 1214-277 come from
HST program 14923 (G. Ostlin+ 2023, in preparation), for Tol 1247-232
from HST program 13027 (Puschnig+ 2017MNRAS.469.3252P 2017MNRAS.469.3252P), and for J1156
from HST program 13656 (Hayes+ 2016ApJ...828...49H 2016ApJ...828...49H,
M. Rutkowski+ 2023, in preparation).
The specific observations analyzed can be accessed at
doi:10.17909/4s6m-7255.
See Section 2.
Throughout this paper we use a ΛCDM cosmology with
(H0, Ωm, ΩΛ)=(70km/s/Mpc, 0.3, 0.7).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 86 45 Sample characteristics
table2.dat 62 45 SDSS derived properties
table4.dat 81 45 Size measurements
table5.dat 112 45 Global Lyα, Hα, and FUV measurements
table6.dat 139 45 Derived galaxy properties
table7.dat 89 45 HST imaging for individual galaxies
table8.dat 157 1350 *Surface brightness, WLya, and fesc profiles
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Note on table8.dat: The same number of significant digits are used for all
the entries, even if the errors are sometimes large. The dynamic range
of the measurements is very large, and the errors depend both on the
measurements and the fitting uncertainties. This means that the errors
are often very small far away from the bright galaxy centres, and the
number of significant digits have been chosen to be able to show these
errors.
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See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
V/154 : Sloan Digital Sky Surveys (SDSS), Release 16 (DR16) (Ahumada+, 2020)
J/A+AS/91/285 : HII galaxies spectrophotometric catalogue (Terlevich+, 1991)
J/AJ/121/169 : Imaging and spectroscopy of Tol 1214-277 (Fricke+, 2001)
J/A+A/462/535 : Low-metallicity HII regions and galaxies (Yin+, 2007)
J/ApJS/192/5 : Emission-line galaxies from HETDEX pilot survey (Adams+, 2011)
J/ApJ/738/136 : LAEs between 0.19<z<1.25 with GALEX grism (Cowie+, 2011)
J/A+A/529/A149 : HII regions in low-metallicity galaxies (Guseva+, 2011)
J/A+A/561/A89 : Optical spectroscopy of 24 Ly-alpha emitters (Atek+, 2014)
J/A+A/587/A78 : LARS VIII. Spatially resolved Ha kinematics (Herenz+, 2016)
J/A+A/606/A12 : MUSE-Wide survey: 831 emission line galaxies (Herenz+, 2017)
J/A+A/608/A8 : MUSE Hubble Ultra Deep Field Survey. VIII (Leclercq+, 2017)
J/ApJ/844/171 : Lyα profile in 43 Green Pea galaxies (Yang+, 2017)
J/MNRAS/477/2817 : Luminous Lyα emitters at z∼2-3 (Sobral+, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- ID Sample Identifier used in this work (G1)
9- 12 A4 --- --- [SDSS]
14- 32 A19 --- SDSS SDSS DR8 identifiers (JHHMMSS.ss+DDMMSS.s)
34- 38 F5.3 --- zspec [0.026/0.24] SDSS DR8 spectroscopic redshift
40- 40 A1 --- r_zspec Flag on zspec (1)
42- 45 I4 0.1nm EWHa [41/1644] SDSS DR8 Hα equivalent width;
in Angstrom units
47- 47 A1 --- r_EWHa Flag on EWHa (1)
49- 53 F5.2 10-7W logLHa [39.8/42.44] SDSS DR8 log of Hα
luminosity; in erg/s units
55- 60 F6.3 [Lsun] logLfuv [9/11.1] log of GALEX Far-UV luminosity (2)
62- 67 F6.4 mag E(B-V)MW [0.006/0.08] Reddening, E(B-V),
Milky Way contribution (3)
69- 84 A16 --- OName Other (or complete) name (G1)
86- 86 A1 --- f_OName a=Measurements for IRAS 08208+2816 were
from SDSS DR12
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Note (1): Flag as follows:
b = Fricke et al. (2001, J/AJ/121/169)
d = Puschnig et al. (2017MNRAS.469.3252P 2017MNRAS.469.3252P)
c = Guseva et al. (2011, J/A+A/529/A149)
e = Terlevich et al. (1991, J/A+AS/91/285)
Note (2): LFUV=λxLλ/L☉ at λ=1524/(1+z)Å
Note (3): Extinction from Infrared Science Archive, NASA/IPAC
(DOI:10.26131/IRSA537), and
Schlafly & Finkbeiner (2011ApJ...737..103S 2011ApJ...737..103S).
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- ID Sample Identifier used in this work (G1)
9- 13 F5.2 [Msun] logMs [8.34/10.6] log of stellar mass (5)
15- 15 A1 --- f_logMs [a] a=From HST SED fitting (LaXs)
17- 22 F6.3 Msun/yr SFRHa-tot [0.29/36.1] star formation rate, Hα (5)
24- 28 F5.3 mag E(B-V)Neb [0/0.7] Reddening, E(B-V) (6)
30- 30 A1 --- f_E(B-V)Neb Flag on E(B-V)Neb (7)
32- 38 F7.4 --- O32 [0.34/16.7] O32 ratio (8)
40- 45 F6.4 --- e_O32 [0.0001/0.2] Uncertainty in O32
47- 52 F6.4 [-] log(O/H) [7.2/8.6] Metallicity, 12+log(O/H) (9)
54- 60 F7.5 [-] e_log(O/H) [1e-05/0.05] Uncertainty in log(O/H)
62- 62 A1 --- f_log(O/H) Flag on log(O/H) (7)
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Note (5): Total estimates from the SDSS MPA/JHU catalogues,
Brinchmann+ (2004MNRAS.351.1151B 2004MNRAS.351.1151B); Salim+ (2007ApJS..173..267S 2007ApJS..173..267S).
Note (6): Derived using Hα/Hβ from SDSS (DR8).
Note (7): Flag as follows:
b = Fricke et al. (2001, J/AJ/121/169);
d = Puschnig et al. (2017MNRAS.469.3252P 2017MNRAS.469.3252P).
c = based on line fluxes from Guseva et al. (2011, J/A+A/529/A149);
e = based on line fluxes from Terlevich et al. (1993MNRAS.260....3T 1993MNRAS.260....3T).
Note (8): O32 ratio from Runnholm+ 2020ApJ...892...48R 2020ApJ...892...48R as:
[OIII]λ5007Å/([OII]λ3727Å+[OII]λ3729Å).
Note (9): Derived using O3N2 strong line metallicity calibration of
Yin+ (2007, J/A+A/462/535); Runnholm+ (2020ApJ...892...48R 2020ApJ...892...48R).
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- ID Sample Identifier used in this work (G1)
9- 10 A2 --- l_rtot [≥ ] Limit flag on rtot
12- 16 F5.2 kpc rtot [3.23/37.62] Total Lyα aperture
18- 18 A1 --- f_rtot Flag on rtot (10)
20- 21 A2 --- l_rpFUV [≥ ] Limit flag on rpFUV
23- 28 F6.3 kpc rpFUV [0.1/10.64] Petrosian radius, FUV
30- 34 F5.3 kpc E_rpFUV [0/1.4]? Upper Uncertainty on rpFUV (G2)
36- 40 F5.3 kpc e_rpFUV [0/0.6]? Lower Uncertainty on rpFUV (G2)
42- 47 F6.3 kpc rpHa [0.4/14.4] Petrosian radius, Hα
49- 53 F5.3 kpc E_rpHa [0/0.8]? Upper Uncertainty on rpHa (G2)
55- 59 F5.3 kpc e_rpHa [0/0.2]? Lower Uncertainty on rpHa (G2)
61- 62 A2 --- l_rpLya [≥ ] Limit flag on rpLya
64- 69 F6.3 kpc rpLya [0.2/28.1] Petrosian radius, Lyα
71- 75 F5.3 kpc E_rpLya [0.018/6.4]? Upper Uncertainty on rpLya
77- 81 F5.3 kpc e_rpLya [0.01/7.7]? Lower Uncertainty on rpLya
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Note (10): Flag as follows:
a = Lyα is undetected in all circular annuli in this
galaxy, the radius used for photometry and shown here is the
maximum radius to the edge of the chip.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- ID Sample Identifier used in this work (G1)
9 A1 --- Flag Flag (11)
11- 16 F6.3 10+47W/m3 LFUV [0.1/24.1] FUV Luminosity, 10+40erg/s/cm2/Å
18- 22 F5.3 10+47W/m3 E_LFUV [0.002/0.5]? Upper Uncertainty on LFUV
24- 28 F5.3 10+47W/m3 e_LFUV [0.002/0.5]? Lower Uncertainty on LFUV
30- 35 F6.3 10+38W/m2 LHa [0.1/32] Hα luminosity, 10+41erg/s/cm2
37- 41 F5.3 10+38W/m2 E_LHa [0.006/0.8]? Upper Uncertainty on LHa
43- 47 F5.3 10+38W/m2 e_LHa [0.006/0.8]? Lower Uncertainty on LHa
49- 50 A2 --- l_LLya [≤ ] Limit flag on LLya
52- 57 F6.3 10+38W/m2 LLya [0.06/64] Lyα luminosity, 10+41erg/s/cm2
59- 63 F5.3 10+38W/m2 E_LLya [0.04/5]? Upper Uncertainty on LLya
65- 69 F5.3 10+38W/m2 e_LLya [0.03/5]? Lower Uncertainty on LLya
71- 72 A2 --- l_WLya [≤ ] Limit flag on WLya
74- 79 F6.3 0.1nm WLya [1.27/72] Equivalent width, Lyα, Å
81- 85 F5.3 0.1nm E_WLya [0.2/3.5]? Upper Uncertainty on WLya
87- 91 F5.3 0.1nm e_WLya [0.2/3.4]? Lower Uncertainty on WLya
93- 94 A2 --- l_fesc [≤ ] Limit flag on fesc
96-100 F5.3 --- fesc [0.002/0.3] Escape fraction
102-106 F5.3 --- E_fesc [0/0.04]? Upper Uncertainty on fesc (G2)
108-112 F5.3 --- e_fesc [0/0.04]? Lower Uncertainty on fesc (G2)
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Note (11): Flag as follows:
a = The Lyα emission from these galaxies are
potentially underestimated due to uncertain background
subtraction, see Section 3.1.3.
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- ID Sample Identifier used in this work (G1)
9- 13 F5.2 Msun/yr SFRHa [0.15/67.1] Star formation rate,
Hα
15- 18 F4.2 Msun/yr E_SFRHa [0/0.8]? Upper Uncertainty on SFRHa (G2)
20- 23 F4.2 Msun/yr e_SFRHa [0/0.8]? Lower Uncertainty on SFRHa (G2)
25- 29 F5.2 Msun/yr SFRFUV [0.16/65.3] Star formation rate, FUV
31- 34 F4.2 Msun/yr E_SFRFUV [0/2]? Upper Uncertainty on SFRFUV (G2)
36- 39 F4.2 Msun/yr e_SFRFUV [0/2]? Lower Uncertainty on SFRFUV (G2)
41- 46 F6.2 10-10.yr-1 sSFRHa [0.28/110] Specific star formation
rate, Hα
48- 51 F4.2 10-10.yr-1 E_sSFRHa [0/7]? Upper Uncertainty on sSFRHa (G2)
53- 56 F4.2 10-10.yr-1 e_sSFRHa [0/7]? Lower Uncertainty on sSFRHa (G2)
58- 62 F5.3 Msun/yr/kpc2 SSFR [0.002/8.6] Star formation rate surface
density
64- 68 F5.3 Msun/yr/kpc2 E_SSFR [0/0.3]? Upper Uncertainty on WLya (G2)
70- 74 F5.3 Msun/yr/kpc2 e_SSFR [0/0.3]? Lower Uncertainty on WLya (G2)
76- 80 F5.2 10+10Msun Mass [0.04/15.3] Mass
82- 85 F4.2 10+10Msun E_Mass [0.01/0.5]? Upper Uncertainty on Mass
87- 90 F4.2 10+10Msun e_Mass [0.01/0.5]? Lower Uncertainty on Mass
92- 96 F5.2 Myr Age [3.29/88] Age
98- 101 F4.2 Myr E_Age [0.4/8.5]? Upper Uncertainty on Age
103- 106 F4.2 Myr e_Age [0.2/8.5]? Lower Uncertainty on Age
108- 111 F4.2 mag E(B-V)s [0.05/0.4] Stellar extinction
113- 116 F4.2 mag E_E(B-V)s [0/0.01]? Upper Uncertainty on E(B-V)s
(G2)
118- 121 F4.2 mag e_E(B-V)s [0/0.01]? Lower Uncertainty on E(B-V)s
(G2)
123- 127 F5.3 mag E(B-V)n [0/1.2] Nebular extinction
129- 133 F5.3 mag E_E(B-V)n [0/0.2]? Upper Uncertainty on E(B-V)n
(G2)
135- 139 F5.3 mag e_E(B-V)n [0/0.3]? Lower Uncertainty on E(B-V)n
(G2)
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- ID Sample Identifier used in this work (G1)
9- 14 A6 --- Lya HST ACS/SBC observations of Lyα
16- 26 A11 --- Ha HST WFC3/UVIS + ACS/WFC observations of Hα
28- 38 A11 --- Hb HST WFC3/UVIS + ACS/WFC observations of Hβ
40- 53 A14 --- FUV HST ACS/SBC observations of FUV continuum
55- 89 A35 --- Opt HST WFC3/UVIS + ACS/WFC of UV/Optical continuum
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Byte-by-byte Description of file: table8.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- ID Sample Identifier used in this work
(G1)
9- 13 F5.2 kpc Rad [0.1/40.76] Radius (r) of
annulus/aperture
15 A1 --- l_SBFUV Limit flag for FUV SB
17- 25 F9.5 10+42J/s/m/kpc2 SBFUV [0.0003/527] FUV surface brightness
27- 33 F7.5 10+42J/s/m/kpc2 e_SBFUV [0.0002/10]? Negative error on FUV
surface brightness
35- 42 F8.5 10+42J/s/m/kpc2 E_SBFUV [0.0002/11]? Positive error on FUV
surface brightness
44 A1 --- l_SBHa Limit flag for Ha SB
46- 54 F9.5 10+33J/s/kpc2 SBHa [0.0003/233] Ha surface brightness
56- 62 F7.5 10+33J/s/kpc2 e_SBHa [0.0003/4]? Negative error on Ha
surface brightness
64- 70 F7.5 10+33J/s/kpc2 E_SBHa [0.0003/4]? Positive error on Ha
surface brightness
72 A1 --- l_SBLya Limit flag for Lya SB
74- 82 F9.5 10+33J/s/kpc2 SBLya [0.006/375] Lya surface brightness
84- 91 F8.5 10+33J/s/kpc2 e_SBLya [0.006/57]? Negative error on Lya
surface brightness
93- 100 F8.5 10+33J/s/kpc2 E_SBLya [0.005/65]? Positive error on Lya
surface brightness
102 A1 --- l_WLya Limit flag for Lya equivalent width
104- 111 F8.5 0.1nm WLya [0.3/72] Lyman α equivalent
width (12)
113- 119 F7.5 0.1nm e_WLya [0.2/9]? Negative error on Lya
equivalent width (12)
121- 127 F7.5 0.1nm E_WLya [0.2/9]? Positive error on Lya
equivalent width (12)
129 A1 --- l_fesc Limit flag for Lya escape fraction
131- 141 F11.5 --- fesc [0.0001/38632] Lyman α escape
fraction (12)
143- 149 F7.5 --- e_fesc [6e-05/0.3]? Negative error on Lya
escape fraction (12)
151- 157 F7.5 --- E_fesc [6e-05/0.3]? Positive error on Lya
escape fraction (12)
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Note (12): The equivalent widths and escape fractions are derived from
the luminosities measured within an aperture of the given radius.
They are thus cumulative measurements rather than local values.
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Global notes:
Note (G1): Identifiers used in this work --
LARS = from Lyman-α Reference Sample,
Hayes+ 2013ApJ...765L..27H 2013ApJ...765L..27H & 2014ApJ...782....6H 2014ApJ...782....6H
ELARS = this work;
Tol = Tololo; Smith+ 1976ApJS...32..217S 1976ApJS...32..217S
J01156 = short name for SDSS J115630.63+500822.1.
Note (G2): Uncertainties with values of 0 with multiple decimal digits are
shown as such for display purposes. The estimated uncertainties are >0 but
consistent with zero within rounding errors.
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History:
From electronic version of the journal
References:
Hayes et al. Paper I. 2013ApJ...765L..27H 2013ApJ...765L..27H
Hayes et al. Paper II. 2014ApJ...782....6H 2014ApJ...782....6H
Pardy et al. Paper III. 2014ApJ...794..101P 2014ApJ...794..101P
Guaita et al. Paper IV. 2015A&A...576A..51G 2015A&A...576A..51G
Rivera-Thorsen et al. Paper V. 2015ApJ...805...14R 2015ApJ...805...14R
Duval et al. Paper VI. 2016A&A...587A..77D 2016A&A...587A..77D
Herenz et al. Paper VII. 2016A&A...587A..78H 2016A&A...587A..78H
Bridge et al. Paper VIII. 2018ApJ...852....9B 2018ApJ...852....9B
Micheva et al. Paper IX. 2018A&A...615A..46M 2018A&A...615A..46M
Runnholm et al. Paper X. 2020ApJ...892...48R 2020ApJ...892...48R
Puschnig et al. Paper XI. 2020A&A...644A..10P 2020A&A...644A..10P Cat. J/A+A/644/A10
Rasekh et al. Paper XII. 2022A&A...662A..64R 2022A&A...662A..64R
Melinder et al. Paper XIV. 2023ApJS..266...15M 2023ApJS..266...15M This catalog
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 01-Aug-2023